Decomposed Granite or DG as it is known in our area of the Southwestern US has many other names locally and regionally. We would like to clear up some of the mystery surrounding this very popular landscaping material category.

Aliases

When using Decomposed Granite for landscape or pathway uses you might hear it called any of the following depending where you are in the United States.

• DG (an abbreviation for decomposed granite)

• Rock Dust

• Chat

• Granite fines

• Crusher fines

• Pathway fines

While not identical in geologic origin or in production technique, Decorative Stone Solutions places all of these in the category of Decomposed Granite. They all are similarly sized and exhibit the same physical properties when used as a landscape ground cover or pathway material in the landscape.

Geologic makeup:

True DG is obviously granitic in origin, but we use this term much more broadly in the landscape world to include crusher fines of just about any geologic formations.  We’ve seen rock dust from lava scoria, limestone, rhyolite, basalt, dolomite, and marble mining operations just to name a few. All of which are used to accomplish the same thing in the landscaping industry. The creation of decorative and functional groundcovers and pathway surfaces.

Color: 

The earth truly does give us just about every natural color known in the form of rock deposits. Therefore, if you cast a wide enough net one can find an amazing variety of colors in the DG category. (Link here to our DG page). While the locally available colors in Southern California may be predominantly gray and tan, those quarried in areas of Arizona are pinks and reds. If the landscape design calls for a color other than what is locally available, know that it can be sourced, but will come with a much higher cost due to the additional freight required.

Sizing:

The size of decomposed granite (DG) typically ranges from very fine particles (similar to sand, dust or silt) up to small gravel-sized pieces, usually around ¼” or 3/8” in diameter. In most cases the sizing will be referred to as ¼”-Minus or 3/8”-Minus.  The ¼” or 3/8”  corresponds to the largest particle size while the minus refers to the fact that it will go down to much smaller, almost microscopic dust particles.

Here’s a breakdown of the size range and the purpose for the size mix:

• Fines: These are the smallest particles, often like dust or sand, which help bind the material together when compacted.

• Small gravel pieces: These can be up to about 3/8 inch in diameter and provide structural strength to the surface.

The mix of fines and small gravel gives DG its stability and makes it suitable for pathways, patios, and other landscaping uses.

Common mistakes:

• We have seen callouts on landscape plans that have read like this: 3/8"-Minus California Gold DG washed.

• The problem is, if a 3/8” DG were to be put through a wash plant then all the fines would be washed out and the result would be an incredibly expensive  3/8” screened gravel.

• The solution: Specify either a 3/8"-minus product which would be a DG size or a 3/8" screened product which would be a gravel.